The biofuels or biofuels They are substances product of the mixture of organic matter (biomass), endowed with energy value that can be used by engines or internal combustion systems. For instance: bioethanol, green diesel, biogas.
They are also known as “Agrofuels”, since most of them come from the use of products derived from agriculture, such as corn or cassava, and to avoid the positive feature of the prefix “bio-“, since they are also a source of contamination, although not as high as other energy sources.
While the important thing about these substances is their inexpensive and safe origin, they are often mixed with other types of fuel to maximize their performance. Even so, many countries deposit in the development of biofuels the hope of alleviating or replacing the consumption of traditional fuels, such as fossil hydrocarbons.
Most biofuels are obtained through processes of fermentation, anaerobic digestion or transesterification of starches, sugars and vegetable oils, to obtain alcohols, ethers, gases and various forms of fuel substances. This means that its production requires an injection of energy that in certain cases could exceed the energy capacity of the fuel obtained, so for the moment agrofuels are more a form of recycling than an energy solution.
Examples of biofuels
- Biodiesel. The biofuel most in demand in Europe is obtained from vegetable oils, animal fats or microalgae oils, and once mixed with mineral diesel, it can be used in any diesel combustion engine. Its emissions are less harmful than those of normal diesel, since it is a highly hydrogenated and oxygenated fuel, produced from vegetables such as soy, mustard, flax, sunflower, hemp, palm and others.
- Bioethanol. Produced, like most bioalcohols, by the fermentation of sugars or starches in organic matter from the action of microorganisms and enzymes, it is a high purity alcohol that can be used as an additive or substitute for gasoline in certain engines. It is obtained particularly from the fermentation of sugar cane, beets or even wine must, or from various cereals. It is the biofuel with the highest production in the world (40,000 million liters in 2004).
- Green diesel. This type of biodiesel is produced by a hydrocracking biological, that is, the breakdown of large molecules of vegetable oils into small hydrocarbon chains, useful for diesel engines. This occurs in the presence of very specific catalysts and high pressures and temperatures. Similar versions of biogasoline are said to be in development.
- Biofuel gasoline. There are numerous alternative gasoline projects underway, one of which was achieved in 2013, using certain strains of the bacteria Escherichia coli, transform glucose molecules into a certain biogasoline that would not require mixing. While these experiments still require a lot of work to become profitable in quantity, it is estimated that in the coming decades there will be surprising results in the area.
- Biogas. Obtained through the anaerobic decomposition (without oxygen) of organic matter, this hydrocarbon-rich gas is produced at the same time as a solid “digestate” that can be used as a fertilizer. Biogas is combustible, fairly safe, and low-yield, but it can be produced relatively easily from biodegradable waste, manure, or other agricultural waste.
- Syngas. It is a mixture of gaseous hydrocarbons with carbon monoxide and hydrogen, obtained through the partial combustion of organic matter and previous drying and polarization processes. The resulting gas is a fairly efficient fuel gas that can very well be used to obtain other more complex biofuels or be burned in an internal combustion engine.
- Biomethanol. Alternative fuel for internal combustion engines currently in use in China and in the racing car industry. Made from biomass, it is cheaper than ethanol, but more polluting and with lower energy density.
- Mycodiesel. The discovery of the fungus Glocladium roseum of the northern Patagonian forests, capable of converting cellulose into medium-length hydrocarbons very similar to those of diesel, allowed experimentation with this type of substances as biofuel, using genetic technology and other similar microorganisms in order to try to create a Cost-effective and easily available mycodiesel.
- Cellulose ethanol. Using microbial cultures or inedible product waste (which has the great advantage of not replacing food products towards the energy chain, abandoning the food chain), copying a bit the feeding process of ruminants, capable of breaking down these sugars, but in a laboratory. This requires high temperatures and, at the moment, it has not been possible to produce in profitable quantities, so it is a research project.
- Biobutanol from algae. Although it has a very low current yield, biobutanol is perfectly producible from sunlight and the fermentation of certain nutrients from seaweed. This method of converting glucose to butanol is not very efficient, so genetic methods are being sought to optimize the process and speed up the production of fuel.
- Biohydrogen. It is hydrogen produced by algae, bacteria and archaea, whose photosynthetic process is capable of producing the element instead of oxygen, in the presence of the enzyme hydrogenase. This resource is usable as a laboratory chemical supply, but it also contains great potential as a biofuel. The way to control this process and to be able to manufacture the necessary tons of hydrogen to use it in a combustion engine is currently being studied.
- Hydrobiodiesel. Produced by the catalytic hydrogenation of vegetable or animal oils and fats, it is completely compatible with conventional diesel, so it can be used as a fuel for ordinary diesel cycle engines. In this process, long chains of alkanes are obtained that are highly usable for energy.
- Hydrobiokerine. Prepared in turn from hydrobiodiesel, it is obtained by subjecting it to subsequent treatments (isomerization and fractionation) to isolate the hydrocarbon stream in its ideal crystallization and distillation ranges.
- DMF (dimethylfuran). With an energy density 40% higher than ethanol, comparable only to gasoline, this compound can be produced through catalytic mechanisms from glucose or fructose. Dimethylfuran (C6H8O) is chemically stable and, dissolved in water, does not pollute the atmosphere. Many current hopes are pinned on the future of this compound.